Boil the eggs hard for about 10 minutes, quench, peel and cut into slices.
Cut the onion into small pieces and roast in the fat with flour. Add the water or stock and the milk and bring to the boil while stirring, simmer gently for a few minutes, stirring again and again. Cut the ham into small pieces and add to it with the peas and egg slices (3 slices reserve for garnish). Stir in sour cream and chives rolls. Season to taste with salt and pepper.